The answer to this question can be found in the second section of this story, following the background we are given of these two women and their friendship. As they sit there watching the view and knit, Mrs. Slade makes the following observation regarding how Rome is viewed differently by each generation:
"I was just thinking," she said slowly, "what different things Rome stands for to each generation of travellers. To our grandmothers, Roman fever; to our mothers, sentimental dangers--how we used to be guarded!--to our daughters, no more dangers than the middle of Main Street. They don't know it--but how much they're missing!"
It is interesting that Mrs. Slade describes the various response to Rome as relating to danger. For their grandmothers, the threat of Roman fever abounded, meaning that the girls had to be gathered in at a certain hour. For their mothers, various sentimental dangers, presumably regarding the threat of forming inappropriate relationships, was the main danger. However, in spite of these dangers, Mrs. Slade is sure that their daugters are missing out by treating Rome as if it were completely absent of danger.